ASTM D6418-99

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International () for the latest information.times beyond48h are necessary,storage of samples in the En Core sampler at462°C or–1262°C for longer than48h is an option,provided it can be shown that the longer storage time used does not influence the concentrations of the VOCs of interest in the samples,or that the data generated by analysis of the samples meet the DQOs(see Practice D5792).4.6This practice does not use methanol preservation or other chemical preservatives in thefield.As a result,there are no problems associated withflammability hazards,shipping restrictions,or dilution of samples containing low volatile concentrations due to solvents being added to samples in the field.4.7The En Core sampler is a single-use device.It should not be cleaned,or reused,or both.4.8This practice cannot be used for sampling cemented material,consolidated material,or material having fragments coarse enough to interfere with proper coring techniques.5.Apparatus5.1En Core Sampler—The En Core sampler has three components:the coring body/storage chamber,which is volu-metrically designed to collect and store a soil sample of approximately5or25g;an O-ring sealed plunger for nondisruptive extrusion of the sample into an appropriate container for analysis or preservation;and,a slide-on cap having an O-ring seal and locking arm mechanism(see Fig.1). The coring body/storage chamber of the5-g sampler has a volume of3cm3to give a sample size of approximately5g,assuming a soil density of1.7g/cm3.The coring body/storage chamber of the25-g sampler has a volume of14.5cm3to givea sample size of approximately25g,assuming a soil density of1.7g/cm3.The seals of the sampler are provided by three polytetrafluoroethylene-coatedfluoroelastomer O-rings(see Fig.1).The coring body/storage chamber,plunger,and cap of the En Core sampler are constructed of an inert composite polymer.The En Core sampler is certified as clean and should not be reused.There are two stainless steel reusable attach-ments that are used with the En Core sampler.These are a T-handle,which is used to push the sampler into the soil for sample collection;and an extrusion tool,which attaches to the plunger for extrusion of the sample from the coring body/ storage chamber(see Fig.2).Each En Core sampler is supplied with a protective moisture-proof bag for shipment to the laboratory.5.2Minimum/Maximum Thermometer—This is any ther-mometer that registers the minimum and maximum tempera-tures reached during any given period of time in°C and has a range that includes the specified storage temperature in divi-sions of1°C.6.Procedure6.1The size of the En Core sampler used is determined by the size of the sample required by the laboratory procedure that will be used to analyze the sample.If a sample size of approximately5g is required for analysis,the5-g En Core sampler,and not the25-g device,should be used to collectand FIG.1Components of the En CoreSamplerstore the sample.Subsampling from the En Core devices should not be performed to obtain smaller sample sizes for analysis.6.2If volatile contaminant levels in the soil being sampled are not known,it is recommended that three samples be collected at each sampling location using three En Core samplers.If determination of moisture content is required for reporting sample results on a dry weight basis,a fourth sample should be collected from each sampling location using a suitable container.The proper sample preparation method for low-level or high-level volatile analysis 5,6can be determined by screening one of the three samples collected in the En Core samplers for high or low concentrations of VOCs.If a high concentration is present,one of the remaining samples in the En Core devices can be extruded into methanol for high-level analysis;if a low concentration is present,the two remaining samples in the En Core devices can be extruded into two appropriate vials for low-level analysis giving an additional low-level sample for analysis,if needed.For guidance on sample collection,sample handling,and sample preparation methods for volatile organic analysis,see Practice D 4547.For quality assurance considerations related to field sampling,see Guide D 4687.6.3As stated in 4.8,the En Core device cannot be used for sampling cemented material,consolidated material,or material having fragments coarse enough to interfere with proper coring techniques.6.4Sample Collection —The manufacturer’s specific in-structions for operating the En Core sampler and T-handle to collect a soil sample should be followed.The steps involved in sample collection using the En Core sampler are given below.6.4.1Before collecting a sample in the En Core sampler,the plunger rod (see Fig.1)should be positioned so that the plunger can be moved freely from the top to the bottom of the coring body/storage chamber.For sample collection,the T-handle (see Fig.2)should be attached to the sampler,and the plunger should be positioned so that the bottom of the plunger is flush with the bottom of the coring body/storage chamber.This prevents air from being trapped in the device during sample collection.When inserting a coring device into a surface for sample collection,air should not be trapped behind the sample.If this occurs,air can pass through the soil causing VOCs to be lost,or it can cause the sample to be prematurely pushed from the coring device.6.4.2Sample collection should be performed as quickly as ing the T-handle,push the En Core sampler into the soil until the coring body/storage chamber is completely full.It can be verified that the coring body/storage chamber is full by looking into the appropriate viewing hole (either 5or 25-g)in the T-handle (see Fig.2).The coring body/storage chamber is completely full if the small O-ring on the plunger rod (see Fig.1)is centered in the T-handle viewing hole.If possible,look at the viewing hole while the device is in the soil to check if the coring body/storage chamber is completely full.If it is not possible to view the hole when the device is in the soil,remove the sampler from the soil to view the hole.If the coring body/storage chamber is not completely full,quickly insert the device back into the same sampling spot and push harder to fill the coring body/storage chamber.When the coring body/storage chamber is completely full,scrape a spatula across the bottom of the coring body/storage chamber so the surface of the soil in the sampler is flush with the opening of the coring body/storage chamber (see Note 2).Quickly wipe the external surface of the coring body/storage chamber with a clean tissue or cloth.After ensuring that the sealing surfaces are clean,cap the coring body/storage chamber while it is still on the T-handle.This is done by gently sliding the cap onto the coring body/storage chamber with a twisting motion.The cap is5U.S.EPA,1996,Method 5035:Closed-System Purge-and-Trap and Extraction for V olatile Organics in Soil and Waste Samples.Test Methods for Evaluating Solid Waste:Physical/Chemical Methods (SW-846),V ol 1B,Final Update III.6U.S.EPA,1996,Method 5021:V olatile Organic Compounds in Soils and Other Solid Matrices Using Equilibrium Headspace Analysis.Test Methods for Evaluating Solid Waste:Physical/Chemical Methods (SW-846),V ol 1B,Final UpdateIII.FIG.2Reusable Attachments to the En CoreSamplerlocked into position when the grooves on the locking arms seat over the ridge on the coring body/storage chamber(see Fig.1). If the cap of the En Core sampler is difficult to lock into position,the O-ring in the cap(see Fig.1)may be bent out of position,and a new cap should be used to seal the device.A bent O-ring in the cap may result in loss of VOCs from the stored sample(see X1.1.8.2and X1.1.9.2).After the cap is locked into position,the T-handle is removed from the sampler, and the plunger is locked into position by rotating the plunger rod(see manufacturer’s specific operating instructions).N OTE2—For drier soils that are difficult to compact in the sampler, scraping a spatula across the surface of the soil to make itflush with the opening of the coring body/storage chamber may loosen particles of the soil in the coring body/storage chamber.These particles may scatter when the device is capped and may affect the seal between the cap and coring body/storage chamber(see X1.1.9.3).Caution should be used when working with these types of soils to prevent scattering from happening.6.4.3A sample label showing the sample number is attached to the cap of the En Core sampler,and the sampler is placed in its protective moisture-proof shipping bag(provided with each En Core sampler).This bag has a label attached for recording sample name,date collected,comments,and sample number.6.5Sample Storage—The capped coring body immediately becomes a sealed sample storage chamber.A sample can be stored in the sealed coring body/storage chamber at462°C for up to48h.For cases where holding times beyond48h are necessary,storage of samples in the En Core sampler at4 62°C or–1262°C for longer than48h is an option,provided it can be shown that the longer storage time used does not influence the concentrations of the VOCs of interest in the samples,or that the data generated by analysis of the samples meet the DQOs(see Practice D5792).Data showing perfor-mance of the En Core sampler as a storage chamber for samples of three different soil types stored at462°C for48h; 462°C for four days;462°C for48h followed by storage for 5days at–1262°C;and,–1262°C for seven days are given in Appendix X1.6.5.1Storage of samples at462°C can be achieved by placing the protective shipping bag,in which the En Core sampler has been placed,in a cooler with ice,cold packs,or in a refrigerated compartment regulated at462°C.If the optional storage temperature of–1262°C is used as discussed in6.5, the En Core sampler should be stored in a freezer compartment regulated at–1262°C.A minimum/maximum thermometer should be placed with the samples during storage to verify that the temperature requirement is maintained.6.6Arrangements with the receiving laboratory for sample log in,sample handling,required storage conditions,and analysis should be made.6.7Extrusion of the Soil Sample from the En Core Sampler—The manufacturer’s specific instructions for operat-ing the En Core sampler and extrusion tool to extrude the soil sample from the coring body/storage chamber should be followed.The steps involved in sample extrusion from the En Core sampler are outlined in6.7.1.6.7.1At the laboratory,the soil is transferred into the appropriate container without disturbing the integrity of the sample by removing the cap from the coring body/storage chamber and using the plunger to expel the soil into the receiving container(see Note3).This is done by performing the following steps according to the manufacturer’s specific operating instructions:attach the extrusion tool(see Fig.2)to the En Core sampler;rotate the extrusion tool plunger knob into position for sample extrusion;unlock the locking arms of the cap;carefully remove the cap from the sampler;and,push down on the plunger knob of the extrusion tool(see Fig.2)to expel the sample from the coring body/storage chamber directly into the appropriate container for analysis or preser-vation(see Practice D4547).After the sample is expelled from the En Core sampler,the O-ring in the sampler cap should be inspected to make sure that the O-ring was not bent when the cap was placed on the coring body/storage chamber.A bent O-ring in the sampler cap can result in loss of VOCs from the stored sample and should be documented(see X1.1.8.2and X1.1.9.2).N OTE3—Samples that have been stored at–1262°C should be allowed to sit at room temperature for2to3min before extrusion from the En Core sampler,which will facilitate extrusion of the frozen sample from the device.7.Report7.1For guidance on information that should be recorded fora sampling activity,see Guide D4687.8.Precision and Bias8.1Precision—Data on the precision of this practice are to be generated in the near future.8.2Bias—No information can be given on the bias of the sampling/storage procedure described in this practice because there is no standard reference material for sampling soil for VOCs in thefield;however,data have been generated to provide information on the performance of the En Core sampler for storage of soil samples at462°C for48h,at4 62°C for four days,at462°C for48hours followed by storage forfive days at–1262°C,and at–1262°C for seven days7.These data are shown in Appendix X1.9.Keywords9.1En Core sampler;soil sampling;storage of soil samples; volatile organic compounds(VOCs);VOC analysis 7A copy of the research report on the study described in Appendix X1is available from ASTM Headquarters.RequestRR:D34-1012.APPENDIX(Nonmandatory Information)X1.PERFORMANCE OF THE EN CORE SAMPLER TO STORE VOC-SPIKED SOIL SAMPLESX1.1A study was conducted to evaluate the performance of the 5-and 25-g En Core samplers to store three different soil types spiked with an aqueous solution containing nine volatile compounds.The En Core samplers used in this study were manufactured in 1998.The 5-g devices that were used repre-sent lot numbers K018166,K028132,and K038132.The 25-g devices that were used represent lot numbers K218266,K018140,P018138,018134,018135,018126,and 018128.The manufacturer can be contacted for information on these lot numbers.X1.1.1The soils used in the study are representative of different environments and contained native microbial popula-tions.They are a river bank soil having 49%sand,26%silt,24%clay,5.3%organic material,approximately 14%mois-ture,and a dehydrogenase (microbial)activity of 22-mg total product formed (TPF)/g/24h;a mountain soil having 75%sand,13%silt,12%clay,4.3%organic material,approxi-mately 12%moisture,and a dehydrogenase activity of 11mg TPF/g/24h;and,a prairie soil having 67%sand,17%silt,16%clay,1.5%organic material,approximately 8%mois-ture,and a dehydrogenase activity of 17mg TPF/g/24h.X1.1.2The VOCs used in the study are cis-dichloroethylene (CDCE),benzene,trichloroethylene (TCE),toluene,perchlo-roethylene (PCE),ethylbenzene,m/p-xylene,o-xylene,and methylethylketone (MEK).These compounds were selected as the analytes of interest because they are representative of halogenated,aromatic,and polar VOCs typically found in contaminated soils.X1.1.3In the study,soil samples were collected in the En Core samplers from a large container of loose soil and then spiked with an aqueous solution containing the compounds listed in X1.1.2at concentrations of approximately 50mg/L.The spiking solution was injected into the middle of the soil plug in the sampler,after which,the sampler was immediately capped.The 5-g samples were spiked with 250µL of the spiking solution,and the 25-g samples were spiked with 1250µL of the spiking solution to give an approximate concentration of 2.5µg/g of each analyte of interest in the samples.This analyte concentration in the soil was selected to limit the influence of the analytical method on the data.X1.1.4After all samples were spiked and capped,five random samples for each soil type were extruded from each size of En Core sampler into methanol for analysis to givetime-zero concentrations of the analytes of interest.The remaining samples were stored under the storage conditions shown in Table X1.1.Storage temperatures were monitored to make sure they were at the specified temperature.After the samples were held for the appropriate times,they were extruded into methanol for extraction and analysis.The metha-nol extracts of the samples were analyzed using EPA Method 8021B.8X1.1.5To evaluate the data,the mean values of the analytes of interest in the stored samples were compared to their mean values in the time-zero samples by calculating average percent recovery.Before average percent recovery was calculated,the data sets were evaluated for outlier data points as described in Practice D 2777.X1.1.6The data generated by this testing are specific to the experimental design of the study.The data give information on the performance of the En Core samplers for storing soil samples collected from loose soil,spiked with an aqueous solution of selected analytes of interest,and then stored under specific storage conditions.The data generated by this testing also are specific to the soils used in the study,the analytes of interest,the analyte concentrations,and the storage conditions that were evaluated.For other soil types,analytes,analyte concentrations,and storage conditions,these data may not apply.X1.1.7The average percent recoveries of the VOCs of interest from samples of the river bank soil stored in the 5-g En Core samplers are shown in Table X1.2;and,the average percent recoveries of the VOCs of interest from samples of the river bank soil stored in the 25-g En Core samplers are shown in Table X1.3.In each of these tables,the percent relative standard deviation of the concentration values in the stored samples is given in parentheses next to the corresponding average percent recovery value.The percent relative standard deviation of the concentration values in the time-zero samples is given in a footnote to each of the tables.X1.1.7.1As shown in Table X1.2,the VOCs of interest in this study have average percent recovery values ranging from8U.S.EPA,1996,Method 8021B:Aromatic and Halogenated V olatiles by Gas Chromatography Photoionization and/or Electrolytic Conductivity Detectors.Test Methods for Evaluating Solid Waste:Physical/Chemical Methods (SW-846),V ol 1B,Final Update III.TABLE X1.1Storage Conditions for Testing the Disposable En Core SamplersStorage Times Storage ConditionsNo Storage462°C on Ice462°C on Ice for 48h then Refrigerated at462°C462°C on Ice for 48h then Frozen at –1262°CFrozen at –1262°CTime-zero 5samples48h 5samples4days 5samples7days5samples5samples87–102%for storage of the river bank soil samples in the 5-g En Core samplers for all of the storage conditions used in this study.Taking into account the error introduced in preparation and analysis of the samples,these data show little loss of the VOCs of interest from the river bank soil during storage in the 5-g En Core samplers.The mean of the nine average percent recovery values listed in Table X1.2for the analytes of interest in the samples of river bank soil stored at 462°C for 48h is 98%recovery with a standard deviation of 4%and a percent relative standard deviation of 4%.The overall mean of the 36average percent recovery values listed in Table X1.2for the analytes of interest and various storage conditions is 97%recovery with a standard deviation of 4%and a percent relative standard deviation of 4%.X1.1.7.2As shown in Table X1.3,the VOCs of interest in this study have average percent recovery values ranging from 79–102%for storage of the river bank soil samples in the 25-g En Core samplers for all of the storage conditions used in this study.Taking into account the error introduced in preparation and analysis of the samples,these data show little loss of the VOCs of interest from the river bank soil during storage in the 25-g En Core samplers.The mean of the nine average percent recovery values listed in Table X1.3for the analytes of interest in the samples of river bank soil stored at 462°C for 48h is 95%recovery with a standard deviation of 3%and a percent relative standard deviation of 3%.The overall mean of the 36average percent recovery values listed in Table X1.3for the analytes of interest and various storage conditions is 95%recovery with a standard deviation of 6%and a percent relative standard deviation of 6%.X1.1.8The average percent recoveries of the VOCs of interest from samples of the mountain soil stored in the 5-g En Core samplers are shown in Table X1.4;and,the average percent recoveries of the VOCs of interest from samples of the mountain soil stored in the 25-g En Core samplers are shown in Table X1.5.In each of these tables,the percent relative standard deviation of the concentration values in the stored samples is given in parentheses next to the corresponding average percent recovery value.The percent relative standard deviation of the concentration values in the time-zero samples is given in a footnote to each of the tables.X1.1.8.1As shown in Table X1.4,TCE,toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene have average percent recovery values for storage of the mountain soil at 462°C for 48h in the 5-g En Core samplers that range from 90–97%.Average percent recovery values of these compounds from the mountain soil samples stored for 7days at –1262°C are similar,ranging from 91–101%.Taking into account the error introduced in preparation and analysis of the samples,these data show very little or no loss of the six VOCs from the mountain soil during storage in the 5-g samplers under the two different storage conditions.The average percent recovery values for TCE,toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene from the mountain soil samples stored for four days at 462°C and for 48h at 462°C followed by five-day storage at –1262°C in the 5-g En Core samplers are slightly lower,ranging from 80–92%.The same trend is shown in Table X1.4for CDCE and benzene.These compounds have averageVOCsStorage Conditions 462°C/48h 462°C/4Days 462°C/48h then –1262°C/5Days –1262°C/7Days CDCE 91%B (15%)C 96%B (4%)C 89%B (3%)C 98%B (7%)C Benzene 93%(3%)94%(4%)87%(5%)93%(10%)TCE 97%(1%)100%(3%)95%(4%)101%(8%)Toluene 99%(1%)96%(4%)96%(3%)99%(6%)PCE100%(1%)100%(1%)99%(3%)99%(7%)Ethylbenzene 101%(3%)100%(4%)101%(3%)101%(6%)m\p-Xylene 102%(2%)100%(3%)96%(9%)99%(6%)o-Xylene 99%(1%)99%(4%)91%(7%)100%(7%)MEK100%(0%)100%(0%)92%(6%)91%(6%)A Soil 1is a river bank soil (49%sand,26%silt,24%clay,5.3%organic material,and approximately 14%moisture).BAverage percent recovery based on mean values determined for five time-zero samples and five stored samples CValue in parentheses is the percent relative standard deviation of the concentration values in the five stored samples.The percent relative standard deviation of the concentration values in the time-zero samples ranged from 0to 6%for all tests using soil 1in the 5-g device.TABLE X1.3Average Percent Recoveries of VOCs from Samples of Soil 1A Stored in 25-G En Core SamplersVOCsStorage Conditions 462°C/48h 462°C/4Days 462°C/48h then –1262°C/5Days –1262°C/7Days CDCE 91%B (1%)C 94%B (3%)C 81%B (8%)C 90%B (8%)C Benzene 90%(4%)94%(4%)79%(11%)87%(12%)TCE 92%(3%)96%(8%)87%(6%)100%(6%)Toluene 94%(3%)94%(6%)91%(4%)98%(6%)PCE96%(3%)100%(5%)92%(5%)102%(6%)Ethylbenzene 98%(3%)100%(1%)98%(3%)102%(4%)m\p-Xylene 98%(1%)98%(2%)95%(6%)100%(3%)o-Xylene 98%(3%)100%(2%)97%(5%)102%(4%)MEK96%(1%)96%(3%)90%(4%)93%(4%)A Soil 1is a river bank soil (49%sand,26%silt,24%clay,5.3%organic material,and approximately 14%moisture).BAverage percent recovery based on mean values determined for five time-zero samples and five stored samples CValue in parentheses is the percent relative standard deviation of the concentration values in the five stored samples.The percent relative standard deviation of the concentration values in the time-zero samples ranged from 1to 4%for all tests using soil 1in the 25-gdevice.percent recovery values ranging from 84–87%for the samples stored at 462°C for 48h and –1262°C for seven days.While the percent recovery values of CDCE and benzene from the mountain soil samples stored for four days at 462°C and for 48h at 462°C followed by five-day storage at –1262°C are slightly lower,ranging from 69to 77%.The average percent recovery values of MEK from the mountain soil samples stored under the four storage conditions in the 5-g En Core samplers range from 71–83%.These values are lower than would be expected for this less volatile compound,especially when compared to the average percent recovery values of the other VOCs listed in Table X1.4.The reason for the lower average percent recovery values for MEK from the mountain soil may be that the ketone reacts with this soil causing a decrease in MEK concentrations with time.X1.1.8.2As shown in Table X1.5,TCE,toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene have average percent recovery values ranging from 93–98%for storage of the mountain soil samples in the 25-g En Core samplers at 462°C for 48h.Average percent recovery values of CDCE and benzene from samples of the mountain soil stored in the 25-g En Core samplers for 48h at 462°C are 87and 90%,respectively.For four-day storage at 462°C in the 25-g En Core samplers,TCE,toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene have average percent recovery values from the mountain soil samples ranging from 87–96%;and average percent recoveries of CDCE and benzene from these samples are 82and 81%,respectively.In testing storage of the spiked mountain soil samples in the 25-g En Core samplers for 48h at 462°C followed by five-day storage at –1262°C,two of the devices used to store the samples had O-rings in their caps that were bent out of position as discussed in 6.4.2and 6.7.1.Because of this error in capping these devices,the seal between the cap and coring body/storage chamber was compromised.As a result,data for only three of the stored samples were used to calculate the average percent recovery values for this storage condition.As shown in Table X1.5,these values range from 56–69%for CDCE,benzene,and TCE;and 78–93%for toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene.For seven-day storage at –1262°C in the 25-g En Core samplers,TCE,toluene,PCE,ethylbenzene,m/p-xylene,and o-xylene have average percent recovery values from the mountain soil samples ranging from 82–98%;and average percent recovery values of CDCE and benzene from these samples are both 71%.The average percent recovery values of MEK from the mountain soil samples stored under the four storage conditions in the 25-g En Core samplers range from 73–86%.As discussed in X1.1.8.1,these values are lower than would be expected and may be due to a chemical reaction between MEK and the mountain soil.X1.1.8.3Differences in the average percent recovery values of the VOCs of interest in this study from the river bank soil (Tables X1.2and X1.3)and mountain soil (Tables X1.4and X1.5)may be due to the difference in the composition of these soils.As described in X1.1.1,the river bank soil is 49%sand,26%silt,and 24%clay,while the mountain soil containsVOCsStorage Conditions 462°C/48h 462°C/4Days 462°C/48h then –1262°C/5Days –1262°C/7Days CDCE 87%B (10%)C 77%B (10%)C 74%B (7%)C 84%B (11%)C Benzene 86%(11%)74%(12%)69%(9%)84%(12%)TCE 91%(8%)83%(9%)80%(5%)91%(9%)Toluene 90%(5%)83%(7%)86%(2%)97%(8%)PCE96%(4%)89%(6%)90%(5%)99%(6%)Ethylbenzene 92%(7%)90%(6%)90%(10%)96%(16%)m\p-Xylene 92%(2%)86%(6%)89%(2%)101%(5%)o-Xylene 97%(2%)92%(6%)92%(5%)97%(10%)MEK83%(0%)76%(7%)74%(4%)71%(9%)A Soil 2is a mountain soil (75%sand,13%silt,12%clay,4.3%organic material,and approximately 12%moisture).BAverage percent recovery based on mean values determined for five time-zero samples and five stored samples CValue in parentheses is the percent relative standard deviation of the concentration values in the five stored samples.The percent relative standard deviation of the concentration values in the time-zero samples ranged from 3to 8%for all tests using soil 2in the 5-g device.TABLE X1.5Average Percent Recoveries of VOCs from Samples of Soil 2A Stored in 25-G En Core SamplersVOCsStorage Conditions 462°C/48h 462°C/4Days 462°C/48h then –1262°C/5Days –1262°C/7Days CDCE 87%B (8%)C 82%B (11%)C 59%D (17%)C 71%B (25%)C Benzene 90%(11%)81%(14%)56%(18%)71%(30%)TCE 94%(6%)88%(9%)69%(9%)82%(17%)Toluene 93%(6%)87%(5%)78%(5%)89%(12%)PCE98%(6%)92%(4%)85%(4%)92%(11%)Ethylbenzene 96%(4%)94%(4%)90%(2%)98%(7%)m\p-Xylene 93%(4%)91%(3%)92%(2%)98%(7%)o-Xylene 96%(4%)96%(5%)93%(2%)96%(6%)MEK86%(2%)83%(6%)75%(2%)73%(2%)A Soil 2is a mountain soil (75%sand,13%silt,12%clay,4.3%organic material,and approximately 12%moisture).BAverage percent recovery based on mean values determined for five time-zero samples and five stored samples CValue in parentheses is the percent relative standard deviation of the concentration values in the stored samples.The percent relative standard deviation of the concentration values in the time-zero samples ranged from 1to 8%for all tests using soil 2in the 25-g device.DAverage percent recovery based on mean values determined for five time-zero samples and three storedsamples.。